|Publication number||US7580348 B2|
|Application number||US 11/024,124|
|Publication date||Aug 25, 2009|
|Filing date||Dec 28, 2004|
|Priority date||Nov 29, 2002|
|Also published as||US20050135235, WO2004051955A1|
|Publication number||024124, 11024124, US 7580348 B2, US 7580348B2, US-B2-7580348, US7580348 B2, US7580348B2|
|Inventors||Ryo Maruyama, Yoshinari Akakura, Masaki Deguchi|
|Original Assignee||Fujitsu Limited|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (15), Non-Patent Citations (1), Referenced by (7), Classifications (30), Legal Events (2)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This application is a U.S. continuation application filed under 35 USC 111(a) claiming benefit under 35 USC 120 and 365(c) of PCT application JP02/12530 filed on Nov. 29, 2002, which is herein incorporated by reference.
1. Field of the Invention
The present invention relates to a communication apparatus, a control method, a program and a computer readable information recording medium, and, in particular, to a communication apparatus which applies the Internet protocol (IP) or such, and applies a technology of logically widening a data transmission band by grouping a plurality of circuits, a control method of this communication apparatus, a program for causing a computer to execute the control method, and a computer readable information recording medium storing the program.
2. Description of the Related Art
Recently, thanks to a sharp spread of the Internet or such, a demand for IP data communication apparatuses increases. Also, a scope encompassed by such a communication network increases. As a result, a data transmission band required for data transmission between respective communication apparatuses included in the communication network may not be completely covered by a physical single circuit. Therefore, it may become necessary to spread a substantial data transmission band by grouping a plurality of circuits, for example. In such a configuration, in order to ensure a required communication quality, a standby circuit may be provided for allocating an extra traffic occurring upon occurrence of a fault on a working circuit.
In a field of data communication, conventionally, a main purpose of the communication is for transmitting images, text, binary data or such, and thus, upon possible occurrence of a fault on a circuit between opposite communication apparatuses, even once lost data may be restored by a technology called ‘retry’ even if several seconds are taken for recovery from the fault. As a result, no substantial problem may occur. However, since delivery of a motion picture, IP telephone communication or such has recently spread along with the widening of the communication band, a distortion may occur in received data when the above-mentioned retry operation is carried out, and such a distortion may directly be sensed visually or acoustically by a user. In such a case, the user may feel artificiality on the delivered motion picture or such.
As a technology for guaranteeing the quality of transmission data even against such a circuit fault trouble, a method of providing working and standby circuits in such a manner of 1+1, n+1 or such is proposed. That is, upon occurrence of a circuit fault, traffic is transferred from the troubled circuit to a standby circuit (or protection circuit). Such a method may be called a ‘protection switching’ method. However, according to the protection switching method, a redundancy in resources is required since a standby circuit is provided as an extra circuit. In terms of saving an investment for such an extra facility, at most one circuit may be prepared as the standby circuit for each working circuit (in an N+1 protection switching scheme, one standby circuit is provided for N working circuits). Accordingly, even when this method is applied, data guarantee may not be completely made if double fault occurrence in a same channel for example.
In order to solve this problem, so-called link aggregation system is proposed in which a plurality of physical circuits are regarded as a single logical circuit (bundle of circuits), and, upon occurrence of a circuit fault, circuit transmission data is dynamically moved among the bundle of circuits (group) and re-configuration is carried out therein, whereby communication is guaranteed. According to the link aggregation system, a basic purpose is that, consequently, a large band is ensured as a result of all the circuits included in the plurality of circuits being always used basically. That is, in this system, a setting is made such that data may be transmitted by each of all the circuits. Accordingly, when a fault occurs in a circuit transmitting data included in the circuit group, a setting operation should be carried out for determining which circuit should be allocated by which the transmission data in the fault circuit is transferred then (re-configuration). As a result, a considerable time may be required, which may amount more than that in the case of the conventional protection scheme.
That is, according to the link aggregation system, a data flow rate is equalized among the respective circuits of the group, and, when a circuit has a trouble, control is carried out to dynamically transfer the data flow rate of the fault circuit. In such a case, hash operation or such is carried out for a normal circuit when occurrence of a circuit fault is detected, and, based on the calculation result, a determination is made for a transmission circuit allocation scheme adapting for a new circuit situation after the circuit fault. Accordingly, an extra time may be required, and thus, a situation may occur in which the required traffic of the communication network may not be satisfied even during a short period.
Japanese Laid-open Patent Application No. 11-154989 discloses a scheme in which, for the purpose of circuit equalization and improvement of transmission efficiency upon carrying out data transmission with the use of a plurality of communication circuits, a transmission data length is counted, and, according to the count result, data distribution to the channels is controlled. According to this scheme, circuit allocation operation is carried out each time when the thus-accumulated data length exceeds a predetermined value, and thus, a circuit load equalization is aimed at. However, this document does not disclose specific process to be applied for transferring signals upon occurrence of a fault on a certain circuit.
The present invention has been devised in consideration of the above-mentioned problem, and an object of the present invention is to provide a system in which, control is made for signal transmission allocation for a transmission circuit group as in the above-mentioned link aggregation system or such, a time required for the control is effectively reduced, thereby a time required for recovery from a circuit fault or such is reduced, and thus, a desired traffic amount in high-rate data transmission can be ensured.
According to the present invention, a predetermined circuit is set as a standby circuit(s) from among grouped circuits, the other working circuits normally bear a traffic of the standby circuit(s), and, upon a fault occur in the working circuit, a traffic of this working circuit is transferred to the standby circuit(s) in a lump. As a result, it becomes possible to minimize a time required for a recovery from the fault.
Other objects and further features of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings:
An embodiment of the present invention is described in detail with reference to figures.
This apparatus 100 includes a command control part 130 receiving a user's command from a host apparatus; a traffic monitor control part 140 monitoring traffics and controlling traffics of the communication circuits L1 through L4 in response to an instruction signal from the command control part; a distribution control part 140 distributing data to be transmitted among the above-mentioned four communication circuits; a fault monitor and switch control part 150 monitoring the communication circuits for a fault; and a time management part 160 managing a time schedule of operation of the apparatus.
These respective control parts may be realized by means of respective electronic circuits, or may be realized by means of a general purpose computer including one or a plurality or CPUs with memories operated according to a predetermined operation program, which may be downloaded via a communication network such as the Internet, or LAN, or may be loaded from a computer readable information recording medium such as a CD-ROM or such in which the program is previously recorded.
The distribution control part 110 has a distribution control table 111 in an internal memory to be refereed to when the transmission data is actually distributed among the communication circuits L1 through L4, and the contents of the distribution control table 111 may be updated by the traffic monitor control part 140 according to the condition of traffics of the communication circuits L1 through L4 if necessary. Further, this apparatus 100 has a data file storage part 120, in which various sorts of table data or such are stored to be referred to by the distribution control part 110 when it carries out distribution control. The data stored there includes a load rate table, a standby circuit exclusive tag table, an hourly table, traffic history data, a reference value/upper limit determination data or such, described later.
The apparatus 100 is configured to carry out operation in such a manner that the above-mentioned plurality of circuits L1 through L4 used as communication circuits between the own apparatus 100 and the opposite apparatus 200 are grouped, and a data transfer band thereby is logically increased (each circuit rate×number of circuits). Then, transmission traffics on the respective circuits L1 through L4 included in the circuit group are periodically monitored by the traffic monitor control part 140, usage rates of the respective circuits are thus calculated and recognized, and, according to the thus-obtained usage rates, processing of transferring the transmission data, i.e., transmission packets of a specific circuit among the circuit group of L1 through L4 to another circuit is carried out. By carrying out such processing, a circuit having traffic of 0% is dynamically generated thereamong.
The circuit of 0% traffic thus generated is regarded as a ‘protection circuit’ or a ‘standby circuit’. Then, when a fault occurs in a certain circuit included in the L1 through L4 group, transmission packets transmitted by this fault circuit are transferred to this standby circuit in a lump. As a result, instantaneous recovery from the fault condition is achieved, and thus, occurrence of packet loss or such can be effectively avoided.
The above-mentioned processing of transferring of the transmission packets to the other circuit for the purpose of generating the protection circuit is carried out as a result of one circuit from among the four circuits L1 through L4 being determined as the protection circuit when the circuit usage rate of the entirety of the L1 through L4 group is lower than a predetermined ‘distribution determination value’ (AL). Further, when a load increases so that the circuit traffic of the entirety of the L1 through L4 group exceeds the predetermined ‘protection circuit releasing determination value’ (AU), the once generated ‘protection circuit’ is automatically released, and control is carried out such that transmission packets are transferred to this circuit once ensured as the ‘protection circuit’ from the circuit currently having the highest load as described later.
Further specifically, in the apparatus 100, the distribution control part 110 uses a tag number (for example, lower four digits of a transmission destination MAC address or such attached to each packet), and, a given packet is transferred to a specific port (corresponding to a specific circuit from among the four circuits) determined according to the distribution control table 111 in which these tag numbers are previously set, and is transmitted therethrough.
In this state, the traffic monitor control part 140 refers to packet holding states of transmission buffers 171, 172, 173 and 174 from which packets are transmitted to the respective circuits L1 through L4, so as to monitor the traffics of all the circuits L1 through L4 periodically, and, under a condition in which the total traffic amount is lower than a predetermined threshold (distribution determination value AL), processing is carried out such that packets held for the lowest traffic circuit are distributed to other circuits gradually. By repeating this distribution processing, a traffic flow rate in one circuit is made to be 0%, and thus, the standby (empty) circuit (i.e., the above-mentioned ‘protection circuit’) is generated dynamically as mentioned above.
As a result, when a fault occurs in another circuit included in the group, the standby circuit is immediately appropriated therefor. Further, when the total traffic amount of the working circuits exceeds the predetermined threshold (releasing determination value AU), processing packets are transferred to this standby circuit from a circuit having a larger traffic, in sequence (so as to releasing the standby circuit). Thus, control is made to guarantee a necessary band. Further, by repeating the above-mentioned standby circuit generating processing, it is also possible to generate a plurality of ‘standby circuits’, according to the total traffic amount (specifically, in a case where the total traffic amount becomes small).
By this function, it becomes possible to dynamically generate the standby circuit according to the traffic amount. As a result, when a fault occurs in a working circuit, it is possible to immediately transfer the traffic thereof to the standby circuit, and thus, it is possible to improve the reliability of communication. Further, in this function, it is also possible to carry out a control such as to dynamically release this standby circuit allocation so a to guarantee the necessary band when the traffic load becomes high.
As a result of the above-mentioned packet distribution processing, a load of another working circuit thus receiving the distribution for the purpose of creating the standby circuit may become too high. In order to avoid such a situation, in the present apparatus, also for the circuits other than the standby circuit, processing is carried out such that, based on the traffic values of the respective circuits obtained as mentioned above, packets of the circuit having the high traffic is distributed to other circuits among the group.
That is, there may occur a situation in which, after the packet distribution control is carried out, even through the total-traffic amount is lower than the predetermined threshold (distribution determination value), a traffic load concentrates on a specific circuit and as a result, it becomes higher than a threshold. In such a situation, the traffic loads are equalized as a result of processing being carried out such that, without releasing the standby circuit, packets to process may be distributed to the lower traffic circuit from the highest traffic circuit among the currently working circuits.
By carrying out such working circuit load equalization processing, it is possible to avoid an imbalance condition in which, even through the total load amount is not so large, a load rate of a specific circuit is too high. Thereby, it is possible to equalize the usage load rates, not releasing but maintaining the once dynamically generated standby circuit.
Further, in the present apparatus, distribution processing may be carried out when the detected total traffic amount becomes lower than the above-mentioned ‘distribution determination value’ AL, n times, successively within a predetermined monitoring period. Similarly, when the detected total traffic amount exceeds the ‘protection releasing determination value’ AU, n′ times, successively, the vacancy state of the standby circuit may be cancelled, and packet transmission with the use of even this circuit may be carried out. By applying such a dynamic packet-distribution protection-time function in which the n times or the n′ times of increasing or decreasing are required for actually initializing the standby circuit releasing or generation processing, it is possible to avoid a situation in which the distribution is repeated each time when data transmission load increases or decreases in a burst manner, and thus, it is possible to avoid a flip-flop phenomenon (a phenomenon in which generation and releasing of the standby circuit are repeated at short time intervals) of distribution control otherwise occurring due to instantaneous packet concentration or such.
That is, when the ‘distribution processing’ were carried out each time when the detected total traffic amount becomes lower than the predetermined ‘distribution determination value’ AL or exceeds the predetermined ‘releasing determination value’ AU, distribution would not necessarily be carried out actually for achieving an appropriate load rate (rather, in such a case, unnecessary distribution would occur) when the traffic changes in a burst manner, or unnecessary software processing would occur for the distribution processing for a case where the traffic amount changes slightly around the predetermined determination value, whereby the CPU load would increase. In order to avoid such a situation, as mentioned above, a protection time interval (number of times, or a ‘control dead zone’) is preferably provided, and, the actual distribution processing or releasing processing is carried out preferably after the condition for the distribution determination value AL or for the releasing determination value AU is satisfied the predetermined times successively.
Next, the above-described processing is described in detail.
Next, it is determined whether or not any port (circuit) of the circuits L1 through L4 exceeds the predetermined ‘releasing reference value’ U of the detected traffic (circuit load rate) (Step S6). If any, ‘circuit equalization processing’ described later with reference to
The tag numbers assigned to the respective port numbers 1 through 4 (corresponding to the circuits L1 through L4, respectively) in the distribution control table 111 are numbers used for identifying packets to be distributed to the respective circuits. That is, in the above-mentioned example, each tag number corresponds to the lowest four digits of a MAC address of each packet.
In the load rate table shown in
In the above-mentioned ‘standby circuit releasing processing’ shown in
With reference to
based on the above-mentioned upper limit value U and the number of current working circuits D=4. Similarly, the above-mentioned ‘distribution determination value’ AL is obtained as follows (see
based on the above-mentioned lower limit value L and the number of current working circuits D=4.
First, an example of the standby circuit generation processing is described. When the load rate table is as shown in
It is noted that the standby circuit is not necessarily generated by a single time of the above-mentioned processing. Actually, as mentioned above, the standby circuit may be generated as a result of a plurality of times of the above-mentioned processing being carried out initiated by each time of the timer interrupt in the processing of
With reference to
That is, as shown in
In the example of
An example of the ‘circuit equalization processing’ is described next with reference to
As shown in the flow of
Next, operation of recovery from a fault occurring in a working circuit in the apparatus 100 according to the embodiment of the present invention is described with reference to
On the other hand, when the standby circuit does not exist (No in Step S33), conventional recovery processing is carried out. That is, the tag numbers of the fault circuit are distributed to the other circuits in consideration of the entire balance of the load rates of the respective circuits.
Next, as another function of the communication apparatus 100 according to the embodiment of the present invention, a ‘low priority usage function’ is described. By this function, when the protection circuit (standby circuit) is produced in the above-described processing, this protection circuit is made usable by predetermined users of lower priority. It is noted that, when a fault occurs on another circuit, even after the protection circuit is thus made usable by predetermined users of lower priority, immediate transfer of the traffic load of the fault circuit in a lump to the protection circuit is carried out in the above-described processing. As a result, the above-mentioned predetermined lower priority packets cannot be actually transmitted. Further, it is also possible to make a setting such that, not only for a case where a fault occurs, but also for a case where a traffic of a high priority circuit increases much, the protection circuit is released the same as the above. Also in this case, the same as the above, the predetermined low priority packets transmitted by the protection circuit until then cannot be transmitted thereafter.
Further, in addition to the above-mentioned function, when a plurality of protection circuits are generated, they may also be set as being usable by predetermined lower priority users. In this case, it is preferable that these lower priority users are classified according to a priority order corresponding to the number of the thus-generated protection circuits, and thus are assigned to the respective protection circuits. Then, upon fault occurrence on a working circuit, these protection circuits are used to receive the traffic of the fault circuit in such a manner that one having the lower priority is used earlier.
That is, if once generated standby circuits are always kept unused to be prepared for a possible fault occurring on another working circuit, proper effective usage of the resources may not be achieved. The above-mentioned ‘lower priority usage function’ is advantageous in this light. In order to transmit a predetermined sort of data with the use of the standby circuit according to this function, a standby circuit exclusive tag table (see
In this function, when the standby circuit is not ensured, the above-mentioned standby circuit exclusive tags are not managed in the distribution control table, and thus, input data corresponding to the standby circuit exclusive tag is discarded in the distribution control part. On the other hand, when the standby circuit is ensured in the above-described processing, the tags designated in the standby circuit exclusive tag table are set in the distribution control table for the thus-generated standby circuit, and thus, transmission of the relevant packets can be started.
For the tags exclusive to the standby circuits, priority information is set, as shown in
When the above-mentioned standby circuit releasing processing is carried out, in order to select a switching target standby circuit (the standby circuit to which a traffic is transferred actually), the traffic monitor control part 140 searches for the standby circuit of unused state from the distribution control table 111 from among the existing standby circuits. When no standby circuit of unused state exists as result, the standby circuit for which the lowest priority tag is designated is searched for from among the existing standby circuits. The switching target standby circuit is thus determined by means of the search processing, the thus-determined standby circuit is switched to act as a working circuit, and thus, is allocated for the relevant shortfall.
In this low priority usage function, for users who allow a possible time zone in which no data can be transmitted, which time zone may occur depending on a working circuit condition (that is, when the traffic increases), the standby circuit is allocated for data transmission. As mentioned above, this standby circuit exclusive data is discarded and thus is not transmitted until the standby circuit is ensured. Instead, data of relatively high priority other than the standby circuit exclusive data may be transmitted through the working circuits including a possible candidate for the standby circuit. Consequently, the band of the working circuits is guaranteed.
Further, even after the standby circuit is once ensured and therewith the low priority usage function is applied, when a fault occurs in the working circuit, the standby circuit is switched to act as a working circuit immediately. After that, the standby circuit exclusive data is not transmitted. However, after recovery is made from the circuit fault, or after the overall traffic decreases, or such, the standby circuit is again ensured, and thus, the standby circuit exclusive data can be transmitted thereby.
Thus, with the use of the lower priority usage function, control is made in such a manner that, band guarantee is always provided for data of high priority for which data transmission band should be always guaranteed, while, for data of lower priority for which no such guarantee is required, the data is transmitted only in a case where the standby circuit is ensured. As a result, it is possible to effectively use the resources while the transmission reliability is improved.
With reference to
When the standby circuit is generated, the distribution control table 111 is searched, with reference to the standby circuit exclusive tag table (
When the standby circuits are ensured in a case where the lower priority usage function is applied, distribution processing is carried out also for this part.
Thus, when the plurality of standby circuits are ensured, dynamic traffic control may be carried out also for the standby circuit exclusive data. Also in this processing, it is preferable to provide the above-mentioned ‘protection times’, whereby flip-flop phenomenon of the control is avoided.
On the other hand, when any standby circuit which is not used to transmit standby circuit exclusive packets does not exist, it is determined in Steps S42-2, S49 whether or not the plurality of standby circuits are ensured. When the plurality of the standby circuits exist, a circuit thereamong for which a lower priority tag is assigned is switched to act as a working circuit with a higher priority, in sequence (Step S51). At this time, however, when only one standby circuit exists, this circuit is unconditionally switched to act as a working circuit (Step S50).
With reference to
First, it is assumed that the distribution control table is such as that shown in
As a result, data (standby circuit exclusive packets) is transmitted accordingly via the port 3, i.e., the standby circuit, thereby the traffic is changed from the state of
As a result, the two standby circuits are thus ensured, and one circuit (port 3) thereof is used for transmitting data corresponding to the standby circuit exclusive tags ‘200, 34, 2, 79’. On the other hand, the traffic of the port 5 (
Further, it is assumed that, in this state, the fault monitor and switch control part 150 detects a circuit fault (on the circuit of the port 1). In this case, it is assumed that the traffics change to those shown in
Thus, in a case where the plurality of standby circuits are managed, when a necessity arises to switch them to act as working circuits, the standby circuit of currently not used state is searched for and is used to satisfy the necessity first. However, if none has been thus found as a result of the search, the standby circuit in which a low priority tag is managed is used for the same purpose instead. The same manner is applied also when, in any working circuit, the releasing reference value is exceeded in the circuit monitoring processing of
As a further another function of the present embodiment of the present invention, a function (referred to as ‘hourly setting function’) by which: time zones obtained from a time axis being divided in predetermined stages (days of week; a time zone; or such); in each of the thus-divided time zone the above-mentioned distribution reference value for generating the protection circuit (standby circuit) and the releasing reference value for releasing the once generated protection circuit (standby circuit) are set; and further, these values may be altered under control according to a command or such given by a maintenance person or a user, is described next.
In this function, by means of control according to a command or such from the maintenance person or a user, execution/cancellation of the function according to the present invention described above is set for each time zone, and, the apparatus is operated according to the thus-set scheduling. In this function, a tendency of possible occurrence of a sharp traffic increase depending on a time zone is monitored, the protection circuit, i.e., the standby circuit is automatically released to act as a working circuit during a time zone which is determined as a time zone in which it becomes difficult to ensure a necessary data transmission band only within the currently set working circuits, while, when it is determined that the traffic is stabilized so that the time zone is shifted to a time zone in which the protection circuit or the standby circuit may be created, the ‘circuit monitoring and distribution determination processing operation’ of
Further, in this case, it is preferable to take the statistic of the actual traffic in respective time zones (days of week or time zones) obtained as a result of the time axis being divided, and, based on the thus-obtained actual traffic information, the reference value for carrying out the distribution processing for generating the protection circuit (standby circuit) or the protection circuit (standby circuit) releasing reference value are dynamically changed.
Furthermore, it is preferable that, the traffic statistic is collected for a predetermined time zone (a day of weak, a time zone), and, based on the thus-obtained traffic information, scheduling of carrying out/canceling (actually, by means of a ‘distribution flag’ described later) of the above-described function according to the present invention.
For example, an hourly table such as that shown in
Further, in the hourly table shown in
Further, the traffic monitor control part 140 monitors the actual traffic condition of data transmission for each circuit, averages the thus-obtained monitoring data for each time zone, and, stores the average results in traffic history data as shown in
The data thus reflected in the hourly table is actually applied as the distribution reference value and the releasing reference value by the time management part 160 when a predetermined time is reached. The traffic monitor control part 140 carries out the distribution determination processing of
Further, the information (the above-mentioned distribution flag) which may be used for inhibiting the above-mentioned distribution determination processing when a predetermined traffic set in the optimizing table shown in
By taking the statistic of the traffic for each predetermined time zone or each predetermined day of the weak as mentioned above, it is possible to obtain a tendency depending on users' usage ways (or the actual load condition). That is, generally, in terms of the respective days of the weak, the traffic is low on Saturday and Sunday, while the traffic tends to be high on weak days. In terms of time zones, the traffic at the middle of the night is low, for example. Accordingly, by means of the above-described hourly setting function, the distribution reference value, the releasing reference value and the distribution flag can be statically or dynamically controlled according to such an actual traffic increasing/decreasing tendency, so that occasions in which the standby circuits are easy to be created so that immediate recovery from a possible fault of a working circuit may be achieved may be effectively increased.
Also with reference to
When the timer indicates that the thus-set time has reached (Step S74), the time management part 160 starts up (Step S75). Then, the time management part 160 refers to the hourly table (Step S76), reads data (the distribution reference value, the releasing reference value and the distribution flag) to apply for a subsequent period, and applies them in the distribution determination processing of
For this setting value application processing, the traffic monitor control part 140 should not be aware of, and the traffic monitor control part 140 should merely carry out the distribution determination processing of
With reference to
A specific setting manner in this case is described particularly for example. In the setting example B shown in
Further, in the setting example A, for the whole morning between 6:00 through 12:00, based on a tendency that the traffic is large so that the standby circuit cannot be ensued, the distribution flag is set as OFF. When the distribution flag is thus set as OFF, the processing of dynamically controlling the band described above according to the present invention is not carried out, and thus, during this period, the available traffic amount can be used as much as possible.
Thus, it is possible to determine the setting contents (the distribution reference value, the releasing reference value and the distribution flag) previously based on the actual traffic tendency.
Further, setting shown in
With reference to
After the storage of the traffic history data is completed for a predetermined amount, the time management part 160 reads this traffic history data for each day of the weak or each time zone repetitively (Step S84, Step S85), obtains optimum data according to the optimizing table of
As mentioned above, for this setting processing, the traffic monitor control part 140 should not be aware of, and the traffic monitor control part 140 should merely carry out processing of dynamically controlling the data transmission band according to the flow of
With reference to
The distribution optimizing table shown in
As described above with reference to
Thus, according to the configuration of the embodiment of the present invention, it is possible to dynamically create the protection circuit (standby circuit) while ensuring the maximum possible data transmission band if necessary by canceling the once-created standby circuit. Accordingly, it is possible to control preparation of a protection circuit facility requiring an investment foreseeing possible (future) failures to the minimum possible, and also, it is possible to increase occasions in which rapid circuit switching is achieved even when a circuit has a failure. Accordingly, it is possible to control interruption duration of data communication service occurring due to a possible circuit failure to the minimum possible.
Furthermore, the protection circuit (standby circuit) may be used to transmit exclusive low priority data (standby circuit exclusive packets), by which, it is possible to provide such a type of service for a user that, while a fixed band guarantee is be provided, a data communication service is provided at a reduced cost accordingly.
Furthermore, by carrying out alteration of the reference values or ON/OFF scheduling of the function according to the embodiment of the present invention statically or dynamically, it is possible to achieve more effective service operation responding to actual traffic condition.
Further, according to the present invention, for each particular circuit included in the circuit group, load distribution among the circuits can be achieved as a result of dynamic band management and control being carried out. Accordingly, it is possible to avoid load concentration at a certain part of the circuits.
Further, the present invention is not limited to the above-described embodiments, and variations and modifications may be made without departing from the basic concept of the present invention claimed below.
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|U.S. Classification||370/219, 370/235, 370/221, 370/244|
|International Classification||H04L12/711, H04L29/00, H04L12/707, H04L12/891, H04L29/14, G08C15/00, H04L12/24, H04J1/16, H04J3/14, H04L1/22, H04L12/26, H04L1/00, G01R31/08, G06F11/00|
|Cooperative Classification||H04L69/40, H04L45/24, H04L41/0663, H04L1/22, H04L45/28, H04L45/22|
|European Classification||H04L45/24, H04L45/22, H04L45/28, H04L29/14, H04L12/24D3, H04L1/22|
|Mar 18, 2005||AS||Assignment|
Owner name: FUJITSU LIMITED, JAPAN
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:MARUYAMA, RYO;AKAKURA, YOSHINARI;DEGUCHI, MASAKI;REEL/FRAME:015795/0256
Effective date: 20050111
|Jan 30, 2013||FPAY||Fee payment|
Year of fee payment: 4